Next Advance SP2200 - Manual (Page 31)

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SP2200Programmable Syringe
Pump
Publication #1200-02 26 04/29/10
The network address is set using the command “*ADR nn", where "nn" is the pump's network address from 0
to 99. If only one pump is in the network, leave the address at the default address of 0. This will simplify
communications because the address can be left off the commands sent to the pump.
To set the network address, individually attach each pump to the computer. Disconnect the network cable from
the "Network" connector on the pump. Using the "*ADR nn" command, send a unique address to each pump
from 0 to 99. This operation only has to be performed once. The set address will be stored in the pump's non-
volatile memory and will take affect immediately. Once the set address command is sent, the pump will only
respond to commands sent to the set address.
To query a pump's current network address, send the command "*ADR" without any parameters. The pump
will respond with its current pump address in the response packet's data field.
8.3 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
Communications to and from the pump use the following data frame:
Supported RS-232 Data Frames
Baud rate:
19200
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.
Two packet protocols are supported, Basic and Safe. The enabled communications protocol is stored in non-
volatile memory, and therefore will be in affect at power up. Safe Mode provides a safer communications
protocol than Basic Mode. Safe Mode detects corrupted data and loss of communication, as well as
automatically transmitting status packets when an alarm occurs.
Considering that the 19200 baud rate communicates at 52 s per bit, a small glitch on the RS-232 cable,
flipping a single bit, can convert a transmitted infusion rate of 100 ml/hr into 900 ml/hr, the need for the Safe
Mode in a production environment is evident. However, Basic Mode is excellent for simplifying early
development of a control program.
While in the Basic Mode, the pump will accept either communications protocol, Basic or Safe. Though the
response packet will be in the current communications mode. This allows a computer’s communication’s
driver to be designed with just one mode. A Safe Mode communications driver can send a ‘SAF’ command to
the pump in the Safe Mode protocol while the pump is in Basic Mode. The response to the ‘SAF’ command,
enabling Safe Mode, would then be in the Safe Mode protocol.