B722-40-880 Issue F
Page 30 © Edwards Limited 2013. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Installation
3.7.5 Command set
Table 15 shows a summary of the full set of commands available for controlling and monitoring the DX pump.
Table 16 shows the abbreviations that are used to define commands in the following sections and Table 17 shows the 
error codes that might be returned.
3.7.6 Simultaneous parallel and serial operation
The pump can be controlled using Parallel Interface control inputs and at the same time monitor various pump 
parameters using the Serial Interface. Alternatively, the pump can be controlled using commands sent over the Serial 
Interface while at the same time monitoring the Normal signal and Analogue Output over the Parallel Interface. 
Figure 11 shows a schematic diagram of a system that demonstrates how to do this.
The pump cannot be controlled using both the Parallel and Serial Interfaces simultaneously. For example, if the pump 
is started by sending a Start command over the Serial Interface, the pump cannot then be stopped by using the Start 
/Stop switch on the Parallel Interface. The pump will ignore the state of the Start / Stop switch on the Parallel 
Interface. To stop the pump, send a Serial Stop command. Only when the Serial Stop command has been received by 
the pump can any commands sent via the Parallel Interface be acted on. 
Similarly, if the pump is started using the Start switch on the Parallel Interface, the pump cannot then be stopped 
by sending a Stop command over the Serial Interface. The pump will ignore any Start or Stop commands received over 
the Serial Interface. To stop the pump, use the Parallel Stop switch. Only when the pump has been stopped using the 
Parallel Interface switch will any Start or Stop commands be accepted via the Serial Interface.
Table 15 - Summary of commands that can be sent to the DX pump
Object name Command
Parameter 
range
Factory 
setting
Data 
type
Units Comments
Node !S850
?S850
0.99 - decimal address Multi-drop address
0 = disable multi-drop address
99 = wild card
Pump type ?S851 7;
10;
4
-string
string
string
chars
chars
chars
Pump type
DSP software version number 
(D39647631x for EXT75DX) and 
D39648601x for EXT255DX)
Full speed RPS (1500 for EXT75DX 
and 1000 for EXT255DX)
Pump control !C852 0
1
- decimal - Stop the pump
Start the pump
?V852 0.1800;
32-bits
- decimal
hex
RPS
flags
Measured motor speed
System status word
Vent options !S853
?S853
0
1
2
3
4
5
6
7
8
0 decimal Hard vent only when <50% speed
Controlled vent if >50% speed or 
hard vent if <50% speed
Hard vent if stop or hard vent if fail 
and <50% speed
Hard vent if stop or controlled vent 
if fail and >50% speed or hard vent if 
fail and <50% speed
Hard vent if fail 
or hard vent if stop 
and <50% speed
Hard vent if fail or controlled vent if 
stop and >50% speed or hard vent if 
stop and <50% speed
Hard vent if stop or fail
Same as option 6
Vent = Permanently Enabled (Fan)