New Era NE-1000 Multi-Phaser Programmable Syringe - Manual (Page 37)

New Era Pump Systems Inc.
www.SyringePump.com
Model NE-1000 Multi-Phaser™
Publication #1200-01 32 08/01/14
on the next pump in the network. Up to 100 pumps can be networked together with a computer. See section
11, 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 6.12, ‘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.
10.2 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 on the display until the pump is powered off or until ‘Setup
Configuration’ is entered.
Communications to and from the pump uses 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.
Two packet protocols are supported, Basic and Safe. The enabled communications protocol is stored in non-
volatile memory, and therefore will be in effect 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 µs 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, although 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, will then be in the Safe Mode protocol.
10.2.1 RS-232 General Syntax Legend
The following syntax expansion legend is common to all syntax expansions:
Except where indicated, all command and response characters are ASCII data.