Appendix B: Computer Remote Command Protocols
Contents
1. command should precede the See note at end of this document on how fo set RPM given tubing type inside diameter and desired flowrate Command Mode Description R l Read Display Return dXX XXca Where d is the direction status a space if stopped if CW if CCW XX XX is the speed status in rom 48 00 at full speed A c is the control status K if started through the keypad R if started through the contacts or set to remote mode through GSIOC a is the autostart condition if in autostart condition display flashing a space if not in autostart Default return 12 50K when the pump is new S B Set the mode SK for Keypad control SR for Remote control Any other letter following the S is ignored If the pump has been enabled by the Run signal on its back panel ine pump will ignore this command to change mode The computer should check the results of this com mand by issuing the command Command Mode Description V l Request Analog Input Status Return vvv Where vvv is a 3 digit decimal number ranging from 00O to 255 A response of 255 corresponds to 5V or open circuit The last character of the returned message has its high bit set Command Mode Description B Set Select Code Inn Where nn is the new select code for this instrument The new code can range from OO through 63 This command instruct2. for a flowrate of 0 2 mL min for example the computer will have to calculate an RPM value of 0 2 x 144 or 28 8 RPM The corresponding R command would then appear as R2880 GSIOC Connector Following is the pinout information for the 9 pin GSIOC connector Pin Name reserved slave data master data clock optional ground reserved slave data master data clock wo eon aD OFF WwW Ne 26
3. Introduction Description Physical Connections PUMP Appendix B Computer Remote Command Protocols Any computer with an RS 422 serial interface port can be used to control the Rainin RP 1 Peristaltic Pump Interface adapters are commercially available to convert RS 232 ports to RS 422 Software for controlling the RP 1 from an external computer must use specific RS 422 protocols described in the follow ing paragraphs The RS 422 bidirectional communications channel allows the computer to communicate with up to 64 slave devices with unique unit ID numbers desig nated as units O through 63 The computer communicates with one pump at a time by transmitting the pump s unit ID The pump which recognizes the unit ID connects to the channel and any other selected device disconnects All connections are made with 9 pin sub miniature D connectors and cabling as shown in Figure 1 COMPUTER RESERVED RESERVED IN OUT OUT CLOCK IN CLOCK OUT CLOCK IN CLOCK OUT RESERVED Z Zzjajojajojoj njin joj Figure 10 Data Format Baud rates RS 422 Signal Lines 9 CONDUCTORFLAT CABLE 28 AWG 0 050 SPACING CONNECTORS ARE 9 PIN SUBMINIATURE D TYPE Data communication is asynchronous eight bit even parity consisting of one start bit eight data bits one parity bit and one stop bit RP 1 pumps check for even parity and use even parity when replying Parity err
4. ed commands are instructions and are executed as back ground processes Immediate commands are status requests and are given a higher priority The RP 1 will interrupt a buffered command to respond to an immediate command Immediate commands are single letter status requests with immediate priority Buffered commands will be interrupted to complete an immediate command Immediate commands from the following RP 1 set can be any valid data character except the following line feed OA hexadecimal carriage return OD hexadecimal pound sign 23 hexadecimal or NAK 15 hexadecimal PWN 22 Command List Immediate commands return messages of one or more characters Each char acter must be sent within 20 milliseconds after the command character has been transmitted The first character is sent as a response to the command The computer gets additional characters in response by sending an ACK 6 hexa decimal The last character of an immediate command has its most significant bit set to 1 The host computer will not ACK it Buffered commands consist of an ASCII string of one or more characters pre ceded by a line feed lt LF gt OA hexadecimal and followed by a carriage return lt CR gt OD hexadecimal The pump echoes with a line feed lt LF gt if ready for a command and with a pound sign lt gt 23 hexadecimal if not ready If not ready the computer retries sending the line feed until the pump echoes a line f
5. eed Once the pump echoes the line feed each subsequent character will be echoed if there is no error If there is an error no echo will be made and the pump will disconnect from the channel If the computer is checking echoes and receives one with an error it can send a NAK 15 hexadecimal and the pump will retransmit the character The pump can be locked put into Remote with the L buffered command When the pump is unlocked it will ignore all buffered commands except the L command A List of the RP 1 immediate and buffered commands follows Command Mode Description Request Contact Input Status Return ab where a reflects pin 3 START STOP input and b reflects pin 1 CW CCW input The allowable values are 1 for an inactive or high input open O for an active or low input closed Default response 11 Command Mode Description R B Set a new speed Rn Sn where n is a 1 4 digit integer interpreted as the value of the new speed in hundredths of a revolution per minute Example R1250 means 12 5 r p m This command changes the speed of the pump if the mode is in Remote control If the speed given requires an increase in rotation rate a ramp is calculated and executed If the new speed is less than the present rotation rate the effect is almost immediate 23 Where direction Cj command and speed CR command are to be used this R
6. or causes the pump to disconnect from the RS 422 channel This can be cor rected by reconnecting then restarting the message Baud rates are 600 1200 2400 4800 9600 and 19200 The clock will run at 16X the baud rate RP 1 pumps operate at 600 baud with their internal clocks If no clock signal is supplied the pump will communicate at 19200 baud 21 Connect Disconnect Sequence Before connecting to a particular pump the computer must first send a discon nect code 255 FF hexadecimal The computer waits 20 milliseconds to allow any active device to turn off its driver Then the computer sends the desired pump s unit ID number as an eight bit byte with the most significant bit set add 128 to the unit ID number The pump that recognizes the unit ID connects its transmitter to the communi cations channel and echoes the unit ID Any device which does not recognize the unit ID will disconnect The active pump will echo its unit ID within 20 mil liseconds after receiving it if no response is received in that time the com puter may assume the pump is unavailable The selected pump remains con nected until the disconnect code or the unit ID of another device is received The connect disconnect flow chart is shown below DISCONNECT ALL DEVICES SELECTED DEVICE Figure 9 Connect IS CONNECTED Disconnect Sequence Commands Two types of commands can be sent via the RS 422 channel buffered and immediate Buffer
7. or keypad mode R is for remote mode X is External Input Mode from back panel e is for Error status This is normally a blank If the Stop key is hit this field becomes S Once read by this command it returns to being a blank again d is direction of rotation F for forward CW when viewed from above and B for backwards CCW This definition does not require the pump to be running s is S for stop no motion or F for flowing rotating This is inde pendent of the panic stop error logic 25 Because the command buffer is 40 characters long a buffered command string can be as long as 39 characters the last character being the CR carriage return ASCII code Note Users want to set flowrates in mL min while the pump must be controlled in RPM For the conversion the computer will need to know the tubing materi al inside diameter and flowrate at some specified RPM This information is contained in the table below Note that the conversion factor RPM per unit flowrate can be obtained by dividing the MaxRPM always 48 RPM for this pump by the Max flowrate value listed in the user manual column of that name For Polyvinyl Chloride PVC tubing of inside diameter 0 25 mm the Max flowrate listed is 0 33 mL min this value presumes 48 RPM The com puter will need to form a conversion factor of 48 0 33 or 144 for this user specified tubing When the user s method asks
8. s the instrument to immediately change its select code because it will be selected through this new code for all future commands The pump must be locked for this command to have any effect Command Mode Description l Module Identification Return RP1V1 x Identifies the pump as a RP7 pump Note Should be V1 9 or larger If not call Technical Service 800 543 4030 for newer chips Command Mode Description j B Set Direction jF for forward CW jB for Backwards CCW Sets pump s motor direction Can be read in d field of command This command has the side effect of starting the pump just as the circu lar arrow keys do from the front panel If the pump is stopped this com mand will start it rotating at the currently defined rate If the pump is already rotating in the direction specified by this command this com mand has no effect If the pump is rotating this command will reverse the pump s direction The R command used to set the rotation rate should precede this command Command Mode Description L B Lock Enable Remote Control Only the Stop key remains active Pushing it once is enough to gener ate a Panic Stop condition Command Mode Description U B Unlock Exit Remote Control Releases the pump from remote control returning control to the key board Command Mode Description l Request Status Return ceds where War c is control status K is f
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