ControlLogix Gateway to DH+

The ControlLogix Gateway can act as a gateway to DH+, from DH+, ControlNet or Ethernet, using the 1756-DHRIO module. This module has two available channels, A and B, both of which may be configured for either DH+ or RIO. It will not act as a gateway to RIO.
Routing which comes in to the ControlLogix Gateway on ControlNet or Ethernet, and goes out on DH+ is specified using a format similar to that of the Pyramid Integrator Gateway (5820-EI). The structure consists of:
  • a DTSA_AB_DH_OFFLINK structure. This specifies the RSLinx Classic driver ID, and the final destination link ID and station number.
  • extra, variable-length information following the end of the DTSA_AB_DH_OFFLINK structure. This extra information specifies how to get from the RSLinx Classic driver to the desired channel on the 1756-DHRIO module.
The structure is defined as:
#define DTSA_AB_DH_ASA_PATH struct dtsa_dh_asa_path
DTSA_AB_DH_ASA_PATH
{
unsigned long atype; // Note: This begins a DTSA_AB_DH_OFFLINK
long driver_id;
unsigned short wControl;
unsigned char bLocalDST;
unsigned char bDLSAP;
unsigned short wDLink;
unsigned short wDStn;
unsigned char bSLSAP;
unsigned short wSLink;
unsigned short wSStn;
unsigned char bLftm; // Note: This ends a DTSA_AB_DH_OFFLINK
unsigned long dwLength;
unsigned char baPath[1];
};
The following special rules apply to the use of the offlink addressing fields in this structure.
  • bLocalDST is ignored and should be set to 0. If it is needed, it will be extracted from the appropriate fields in baPath[].
  • The address must contain a valid link ID and it must not be a local address (for example, wControl must be DTL_ROUTEFLAG_BRIDGETYPE_RAW, not DTL_ROUTEFLAG_BRIDGETYPE_NONE). It is not necessary to fill in the source LSAP, link ID and station number. They should be set to zero. The 1756-DHRIO will determine the source link ID and will return it as the destination link ID in the reply packets.
  • dwLength specifies the number of bytes contained in baPath[]. baPath is always at least 3 bytes long. The final 3 bytes of baPath are always
    01 [slot][channel]
     where [slot] is the 0-based slot number of the outbound 1756-DHRIO module, and [channel] is 2 for Channel A, or 3 for Channel B.
Specific path sequences for common routes
  • Ethernet to DH+ via the RSLinx Classic Gateway driver (TCP -n)
    Configure an RSLinx Classic Gateway client driver to connect directly to the 1756-ENET module. Enter the IP address of the 1756-ENET module; leave the channel name blank.
    dwLength = 3, baPath = 01 [slot][channel]
  • ControlNet to DH+ via the DTC driver (AB_KTC -n)
    dwLength = 5, baPath = 02 [MAC ID] 01 [slot][channel]
    where [MAC ID] is the ControlNet MAC ID (node address) of the 1756-CNB module in the ControlLogix Gateway.
  • DH+ to DH+ via the KTX (AB_KT -n)
    For DH+ to DH+ routing, this structure is not used; configure an appropriate link ID in the routing table of the 1756-DHRIO modules, and use the regular DTSA_AB_DH_OFFLINK.
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