SNAP PAC Controller Comparison

Opto 22 SNAP PAC programmable automation controllers are available in three forms:

  • Standalone PAC (S-series)
  • Rack-mounted PAC (R-series)
  • Software-based PAC for PC-based control (SoftPAC)

This chart compares features for the latest SNAP PACs, with minimum firmware version R10.0 and PAC Project software R10.0.

For additional information, see the PDF, SNAP PAC Controller Comparison Chart.

  Software Standalone Rack-mounted
Maximum PAC Control charts running at once (plus default host task) 64 32 32 16 16
Ethernet (UDP/IP, 10/100 Mbps)
Two independent Ethernet network interfaces a
Number of RS-485 serial ports b 1 4c 0 0
Number of RS-232 serial ports   2 4c 1 1
EtherNet/IP (Allen-Bradley RSLogix systems, others)  
Modbus/TCP (slave)  
OPC driver support
OptoMMP memory-mapped protocol d
SNMP (network management)  
FTP server, file system  
FTP client
Email (SMTP client with authentication and attachments)
Supports Node-RED via SNAP-PAC nodes and RESTful API  
Direct access to hard drive & network drives (Dropbox, etc.)        
Real-time clock a
Backup battery (recharges when PAC has power)f  
Physical RAM
RAM available for strategy
Non-volatile or batter-backed RAM
Flash memory
Data storage space
64 MB
8 MB
32 MB
16 MB
8 MB
16 MB
~2.5 MB
32 MB
16 MB
8 MB
16 MB
​~2.5 MB
16 MB
4 MB
2 MB
8 MB
​~2 MB
16 MB
4 MB
2 MB
8 MB
​~2 MB
Removable data storage (microSD card slot) a 32 GB maxh 32 GB maxh 32 GB maxh 32 GB maxh
32-bit processor and floating-point unit (FPU) a
Floating-point unit (FPU) a
Compatible with SNAP PAC EB (Ethernet) brains
Compatible with SNAP PAC SB (serial) brains      
Compatible with groov EPIC 
Compatible with groov  RIO
Combination controller and I/O processorm n/a n/a n/a
Mounts on SNAP PAC I/O mounting rack  n/a n/a n/a
Mounts on SNAP B-series I/O mounting rack       p  

Maximum number of modules allowed on largest rack: Any mix of 16 digital, 16 analog, and 8 serial

n/a n/a n/a n n
Power requirements a 8-32 VDCi
10 W-11.3 W max
8-32 VDCi
​10 W-11.3 W max
5.0 to 5.2 VDC
@ 1.2-1.5 A
5.0 to 5.2 VDC
​@ 1.2-1.5 A
Operating temperature (degrees C)
Storage temperature (degrees C)
a -20 to 60
-40 to 85
-20 to 60
​-40 to 85
-20 to 60
​-40 to 85
-20 to 60
​-40 to 85
Humidity (non-condensing) a 0-95% 0-95% 0-95% 0-95%
a As provided by the Microsoft Windows-based computer SoftPAC runs on. 
b SoftPAC cannot communicate through serial ports on the PC.
c Serial ports are software configurable for RS-232 or RS-485.
d SoftPAC includes Status Read, Status Write, and Scratch Pad areas of the memory map.
e Function of Flash memory is implemented via a file; size is limited only by available disk space.
Models manufactured before August 2007 and S1s with serial numbers 625653 and lower have 3-volt CR2032 lithium battery.
g This part is Obsolete, please contact Opto 22 Pre-Sales Engineering for more information.
h Requires firmware 9.4a or higher and loader 6.1a or higher for 32GB capacity; lower versions limited to 2GB.
i Units with serial numbers lower than 500,000 have an 8-24 VDC input voltage rating. Verfiy voltage on the  unit's faceplate before applying power.
m I/O features vary by model. For details, see form 1677, SNAP PAC Controller and Brain Comparison Chart.
n All SNAP-RAC-R1-Bs, and SNAP-PAC-R1s with serial numbers lower than 600,000 are limited to eight 4-channel digital modules per rack.
Only applies to SNAP-PAC-R1-B (Obsolete)