Next Advance SP1800 - Manual (Page 38)

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SP1600/1800 Programmable Syringe Pump
Publication #1200-02 33 9/15/04
9. RS-232 Communications
The SP1600/SP1800 Syringe Pump can communicate with any computer or device
with an RS-232 communications port.
9.1 Connection and Networking
On the rear of the pump are 2 square RJ-11 (“phone jack” style) sockets. Connect the RS-232
cable into the socket labeled “To Computer”. Connect the other end to the serial port on the computer, or
other control device. Turn power off to the pump and the computer before connecting cables.
If the pump is part of a pump network, connect a pump network cable between the socket labeled “To
Network”, on the first pump, and the socket labeled “To Computer” on the next pump in the network.
Repeat for each pump in the network, connecting the “To Network” socket of one pump to the “To
Computer” socket on the next pump in the network. Up to 100 pumps can be networked together with a
computer. See section 10, Logic Interface: TTL Input and Output, for a diagram of the rear of the pump.
When communicating with a pump in a multi-pump network, each preceding pump in the network must
be powered on.
Each pump in the network needs a unique network address to identify the pump to the computer. Network
addresses are from 00 to 99. If the network consists of only 1 pump, set the pump’s address to 0. Also,
each pump needs to be set to the same baud rate as the computer. Use the ‘Setup’ function on the keypad
to set the network address and the baud rate. See section 5.12, ‘Setup’ . The '*ADR' command can also
be used to set the network address.
The supported baud rates are 300, 1200, 2400, 9600, and 19200. The trade-off on baud rates is
communications speed versus noise immunity. For most environments, 19200 would be acceptable. But
in environments that are electrically noisy and/or over long cables, the communications signal may
degrade or be disrupted, causing communications errors. In these situations, a lower baud rate may
improve the reliability of the communications.
9.2 RS-232 Protocol:
When the pump is used in a multi-pump network configuration, precede each command with a pump
address. Pumps will ignore all commands that do not have their defined network address. If the network
address is not specified in the command, the address will default to 0.
After a command is sent to the pump, the pump will not accept any further communications until the
current command has been processed. Completion of the command processing is indicated when the first
byte of the response packet is transmitted. While the user is changing data or configurations from the
keypad, command processing is delayed.
A triangle appears in the upper left corner of the LCD display after the pump has received valid
communications. This triangle remains in the display until the pump is powered off or until ‘Setup
Configuration’ is entered.
Communications to and from the pump use the following data frame:
Supported RS-232 Data Frames
Baud rates:
19200, 9600, 2400, 1200, or 300
Frame: 10 bit data frame (8N1):
Start bit:
1
Data bits: 8
Stop bits: 1
Parity:None
Every command received by a pump in the network is acknowledged by the pump with a response packet
that includes a status character indicating the current operational state of the pump.